Method of detecting and responding to a cooling system failure in a power supply device

Abstract

A cooling fan of a secondary battery and a cooling fan of a DC/DC converter are arranged in parallel to share the same air discharge path. A temperature sensor on an air intake side and a temperature sensor on an air discharge side are attached to the secondary battery. When the cooling fan is in failure, a temperature deviation between the air intake side and the air discharge side in the secondary battery increases because a backflow component of a discharge air is generated through the discharge path as the cooling fan operates. Based on this phenomenon, when operation commands for both of the cooling fans are issued, the control circuit senses a failure in the cooling fan by monitoring the temperature difference between temperatures detected by the temperature sensors. Failure detection is thereby possible without providing a sensor at each of the cooling fans.

1. A power supply device comprising:
 a first voltage generator having a first coolant path allowing a coolant for cooling the first voltage generator to pass therethrough; 
 a second voltage generator having a second coolant path allowing the coolant for cooling the second voltage generator to pass therethrough; 
 a first cooling system supplying the coolant to a coolant intake side of said first coolant path; 
 a second cooling system supplying the coolant to a coolant intake side of said second coolant path; 
 a coolant discharge path connected to both of a coolant discharge side of said first coolant path and a coolant discharge side of said second coolant path; 
 a first temperature sensor attached to said first voltage generator; 
 a second temperature sensor attached to said first voltage generator on the coolant discharge side of said first coolant path, relative to said first temperature sensor; and 
 a control circuit controlling an operation of each of said first and second cooling systems, 
 when said control circuit issues an operation instruction to each of said first and second cooling systems, said control circuit detecting failure in said first cooling system when a temperature difference between temperature detected by said first temperature sensor and temperature detected by said second temperature sensor is larger than a reference value. 
 
   
   
     2. The power supply device according to  claim 1 , further comprising a third temperature sensor attached to said second voltage generator, wherein
 when said control circuit operates said second cooling system to cool said second voltage generator based on a temperature detected by said third temperature sensor, said control circuit also operates said first cooling system in an auxiliary manner to prevent the coolant discharged from said second coolant path from flowing back to said first coolant path through said coolant discharge path even when it is determined that cooling of said first voltage generator is unnecessary based on the temperatures detected by said first and second temperature sensors. 
 
   
   
     3. The power supply device according to  claim 2 , wherein a flow rate of the coolant from said first cooling system when said first cooling system is operated in said auxiliary manner is set to be lower than a flow rate of the coolant when said first cooling system is operated to cool said first voltage generator. 
   
   
     4. The power supply device according to  claim 1 , wherein
 said first voltage generator is a secondary battery, and 
 said second voltage generator is a power converter having a semiconductor power switching element embedded therein. 
 
   
   
     5. A power supply device comprising:
 a first voltage generator having a first coolant path allowing a coolant for cooling the first voltage generator to pass therethrough; 
 a second voltage generator having a second coolant path allowing the coolant for cooling the second voltage generator to pass therethrough; 
 a first cooling system for supplying the coolant to a coolant intake side of said first coolant path; 
 a second cooling system for supplying the coolant to a coolant intake side of said second coolant path; 
 a coolant discharge path connected to both of a coolant discharge side of said first coolant path and a coolant discharge side of said second coolant path; and 
 a control circuit controlling an operation of each of said first and second cooling systems, 
 when said control circuit operates one cooling system of said first and second cooling systems, said control circuit also operating the other cooling system of said first and second cooling systems even when cooling of the voltage generator corresponding to said other cooling system is unnecessary. 
 
   
   
     6. The power supply device according to  claim 5 , wherein said control circuit controls the operation of each of said first and second cooling systems, based on an output of each of temperature sensors provided at said first and second voltage generators. 
   
   
     7. The power supply device according to  claim 5 , wherein, when said control circuit operates said one cooling system, and when said control circuit also operates said other cooling system even when cooling of the voltage generator corresponding to said other cooling system is unnecessary, said control circuit sets a flow rate of the coolant from said one cooling system to be relatively higher than a flow rate of the coolant from said other cooling system. 
   
   
     8. The power supply device according to  claim 5 , wherein
 said control circuit controls the operation of said first cooling system such that said first voltage generator is maintained to be at not more than a first reference temperature, and controls the operation of said second cooling system such that said second voltage generator is maintained to be at not more than a second reference temperature, 
 said first reference temperature is lower than said second reference temperature, and 
 when said control circuit operates said second cooling system to cool said second voltage generator, said control circuit also operates said first cooling system even when cooling of said first voltage generator is unnecessary. 
 
   
   
     9. The power supply device according to  claim 8 , wherein when said control circuit operates said second cooling system, said control circuit also operates said first cooling system even when cooling of said first voltage generator is unnecessary, said control circuit sets a flow rate of the coolant from said second cooling system is set to be relatively higher than a flow rate of the coolant from said first cooling system. 
   
   
     10. The power supply device according to  claim 5 , further comprising:
 a first duct provided between a discharge side of said first cooling system and said first coolant path; and 
 a second duct branching off from said first duct, wherein 
 an intake side and a discharge side of said second cooling system are coupled to said second duct and said second coolant path, respectively. 
 
   
   
     11. The power supply device according to  claim 5 , wherein
 said control circuit controls the operation of each of said first and second cooling systems such that said first and second voltage generators are maintained to be at not more than a control target temperature and a control target temperature, respectively, 
 said first voltage generator is a secondary battery, 
 said second voltage generator is a power converter having a semiconductor power switching element embedded therein, and 
 said control target temperature of said power converter is higher than said control target temperature of said secondary battery. 
 
   
   
     12. A method comprising:
 applying a coolant to a first voltage generator, the first voltage generator having a first coolant path allowing the coolant to pass through the first voltage generator, the coolant being applied by a first cooling system to a coolant intake side of the first coolant path; 
 applying the coolant to a second voltage generator, the second voltage generator having a second coolant path allowing the coolant to pass through the second voltage generator, the coolant being applied by a second cooling system to a coolant intake side of the second coolant path; 
 discharging the coolant from the first and second coolant paths by a coolant discharge path connected to both of a coolant discharge side of said first coolant path and a coolant discharge side of said second coolant path; and 
 controlling an operation of each of said first and second cooling systems by a control circuit, wherein when the control circuit operates one cooling system of the first and second cooling systems, the control circuit also operates the other cooling system of the first and second cooling systems even when cooling of the voltage generator corresponding to the other cooling system is unnecessary. 
 
   
   
     13. The method according to  claim 12 , wherein said control circuit controls the operation of each of said first and second cooling systems, based on an output of each of temperature sensors provided at said first and second voltage generators. 
   
   
     14. The method a according to  claim 12 , wherein, when said control circuit operates said one cooling system, and when said control circuit also operates said other cooling system even when cooling of the voltage generator corresponding to said other cooling system is unnecessary, said control circuit sets a flow rate of the coolant from said one cooling system to be relatively higher than a flow rate of the coolant from said other cooling system. 
   
   
     15. The method according to  claim 12 , wherein
 said control circuit controls the operation of said first cooling system such that said first voltage generator is maintained to be at not more than a first reference temperature, and controls the operation of said second cooling system such that said second voltage generator is maintained to be at not more than a second reference temperature, 
 said first reference temperature is lower than said second reference temperature, and 
 when said control circuit operates said second cooling system to cool said second voltage generator, said control circuit also operates said first cooling system even when cooling of said first voltage generator is unnecessary. 
 
   
   
     16. The method according to  claim 15 , wherein when said control circuit operates said second cooling system, said control circuit also operates said first cooling system even when cooling of said first voltage generator is unnecessary, said control circuit sets a flow rate of the coolant from said second cooling system is set to be relatively higher than a flow rate of the coolant from said first cooling system. 
   
   
     17. The method according to  claim 12 , further comprising:
 a first duct provided between a discharge side of said first cooling system and said first coolant path; and 
 a second duct branching off from said first duct, wherein 
 an intake side and a discharge side of said second cooling system are coupled to said second duct and said second coolant path, respectively. 
 
   
   
     18. The method according to  claim 12 , wherein
 said control circuit controls the operation of each of said first and second cooling systems such that said first and second voltage generators are maintained to be at not more than a control target temperature and a control target temperature, respectively, 
 said first voltage generator is a secondary battery, 
 said second voltage generator is a power converter having a semiconductor power switching element embedded therein, and 
 said control target temperature of said power converter is higher than said control target temperature of said secondary battery.